Mild Evidence for Local Adaptation of Solidago canadensis under Different Salinity, Drought, and Abscisic Acid Conditions

Abstract

Solidago canadensis is an invasive weed that grows successfully under adverse environmental conditions and shows a high capability to various habits. To evaluate the role of local adaptation in the invasion of S. canadensis into heterogeneous environments, the morphological and physiological traits of S. canadensis plants were studied under salt (control, 100 and 150 mM NaCl), drought stress conditions (control, 75 and 100 g L-1 PEG-6000) and abscisic acid (ABA) (0, 25, and 50 ul L-1) application. Salt treatments significantly reduced the plant height, shoot dry weight (SDW), water use efficiency (WUE), intracellular CO2, and net photosynthetic rate (NPR) by 8.17, 28.75, 21.65, 20.71 and 35.44%, respectively than control plants. Among salt treatments, maximum reduction was found under 150 mM NaCl followed by 100 mM NaCl and control treatment. Salt treatments demonstrated a nonsignificant effect on leaf fresh and dry weight, root length and stomatal conductance. Similarly, drought stress significantly reduced the leaf fresh weight, leaf dry weight, plant height, stomatal conductance, and NPR with maximum reduction under severe drought condition (100 g L-1 PEG-6000), where the values were 31.01, 30.39, 35.09, 49.19 and 46.93% lower respectively than control plants. In this study, ABA application had not significantly influenced the morpho-physiological traits of S. canadensis. Reduced plant height, SDW and NPR under both stresses and reduced WUE and intracellular CO2 under salt stress suggest some degree of phenotypic plasticity under these stress conditions.